Thursday, April 3, 2008
Friday, January 25, 2008
We started work on the embodied energy calculator because we’re invested in actually doing something. No more preaching to the choir, we started spreading the word by whispering Carl Elefante’s phrase to anyone who would listen: “psst—the greenest building is the one already built. Pass it on.” Feeling bolder, we said it in meetings. We wrote it in articles. And then we got buttons to help spread the message. These have really caught on, and it’s not just preservationists wearing them these days. Once the people heard the message, we were ready to move again.
Embodied energy has been incorporated into staff reports. Our HPC now considers the embodied energy of every building submitted for demo in town. Every single building. And there’s still a lot of demo in town…
As part of this effort, we wanted to make the number “real” for the community. And so we started working on calculators. First, it makes it easier for staff to report. Second, we can put our numbers into something like gallons of gas… and yes, those MBTUs can be eye popping. It’s helped us go from people listening to a message to people ready to take action. Give it a try in your neighborhood.
We’ve taken small steps, to be sure. But the momentum is just now beginning to build, and we think we’re headed in the right direction. So what’s next? The HPC has begun working on incentives, just as “green” spreads throughout the City. Watch this space as we chronicle what we hope to accomplish.
The greenest building has an HPC behind it!
Saturday, January 19, 2008
The calculators are located at www.thegreenestbuilding.org - check 'em out and let us know what you think. You can figure embodied energy, demolition energy, compare embodied energy to gallons of gas, and even do a complete teardown calculation. With help from MJ, we think we've put together a great site for preservationists to visit. We hope you all find it useful.
We've also now posted the ACHP report discussed earlier on The Greenest Building site for download. So get it and get working!
We'll keep tweaking the page, adding more calculators, and are working on a survey model calculator. If anyone wants to donate graphic design experience, that could probably help us a ton.
The greenest building is calculated.
Monday, January 7, 2008
We really like the site Your Home Technical Manual, sponsored by the Australian government.
We're asked to build "long life, durable and adaptable buildings." Historic homes win on all three! They've obviously had a long life, they're durable, and as anyone who lives in an old home will tell you, are easily adaptable!
Below are excerpts from the site. Visit and click around, there is a lot of great info.
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the acquisition of natural resources to product delivery. This includes the mining and manufacturing of materials and equipment, the transport of the materials and the administrative functions. Embodied energy is a significant component of the lifecycle impact of a home. Every building is a complex combination of many processed materials, each of which contributes to the building's total embodied energy. Renovation and maintenance also add to the embodied energy over a building's life.
It was thought until recently that the embodied energy content of a building was small compared to the energy used in operating the building over its life. Most effort was therefore put into reducing operating energy by improving the energy efficiency of the building envelope. Research has shown that this is not always the case. Embodied energy can be the equivalent of many years of operational energy.
The materials we use to build our homes have many "unseen" adverse environmental impacts.
The importance of embodied energy and other environmental impacts does not become apparent until we examine the materials from a life cycle approach, usually known as Life Cycle Assessment (LCA). LCA examines the total environmental impact of a material or product through every step of its life - from obtaining raw materials (for example, through mining or logging) all the way through manufacture, transport to a store, using it in the home and disposal or recycling. LCA can consider a range of environmental impacts such as resource depletion, energy and water use, greenhouse emissions, waste generation and so on.
Choices of materials and construction methods can significantly change the amount of energy embodied in the structure of a building. True low energy building design will consider this important aspect and take a broader life cycle approach to energy assessment. Merely looking at the energy used to operate the building is not really acceptable. Operational energy consumption is dependent on the occupants. Embodied energy is not occupant dependent - the energy is built into the materials. Embodied energy content is incurred once (apart from maintenance and renovation) whereas operational energy accumulates over time and can be influenced throughout the life of the building.
Research by CSIRO has found that the average household contains about 1,000 GJ of energy embodied in the materials used in its construction. This is equivalent to about 15 years of operational energy use. For a house that lasts 100 years this is over 10 percent of the energy used in its life.
As the energy efficiency of houses and appliances increases, embodied energy will become increasingly important. Reuse of building materials commonly saves about 95% of embodied energy that would otherwise be wasted.
Try to follow these guidelines:
Design for long life and adaptability, using durable low maintenance materials.
Ensure materials can be easily separated.
Avoid building a bigger house than you need. This will save materials.
Modify or refurbish instead of demolishing or adding.
Ensure materials from demolition of existing buildings, and construction wastes are re-used or recycled.
Use locally sourced materials (including materials salvaged on site) to reduce transport.
Select low embodied energy materials (which may include materials with a high recycled content) preferably based on supplier-specific data.
Avoid wasteful material use.
Specify standard sizes, don't use energy-intensive materials as fillers.
Ensure off-cuts are recycled and avoid redundant structure, etc. Some very energy intensive finishes, such as paints, often have high wastage levels.
Select materials that can be re-used or recycled easily at the end of their lives using existing recycling systems.
Give preference to materials manufactured using renewable energy sources.
Use efficient building envelope design and fittings to minimise materials (eg. an energy efficient building envelope can downsize or eliminate the need for heaters and coolers, water-efficient taps allow downsizing of water pipes, etc).
Ask suppliers for information on their products and share this information.
Friday, December 14, 2007
Washington, D.C. (December 13, 2007) – Richard Moe, president of the National Trust for Historic Preservation, tonight called for historic preservation’s “essential role” in fighting climate change, in a speech following his receipt of the National Building Museum’s prestigious 2007 Vincent Scully Prize.
Construction and operation of buildings, Moe noted, contributes 48% of America’s greenhouse gases – nearly double that of cars, trucks, trains and airplanes – and even construction of the greenest new building contributes to global warming. Despite that, Moe said, the most talked about solution to global warming is building new, greener buildings, often destroying an old one in the process. “We can’t build our way out of our environmental problems. We have to conserve our way out. That means we have to make better, wiser use of what we’ve already built.”
. . .
Read Moe's speech here. It is, not surprisingly, great, as the NTHP has been a leader on this issue long before LEED.
and don't forget to check out NTHP's Sustainability Resources
Wednesday, December 5, 2007
The concept model provides a second table for demolition energy. The math is simple. Demolition Energy = Gross s.f. multiplied by the demolition energy of materials per s.f. of construction for buildings of similar size and construction type in table 2.
TABLE 2 Demolition Energy of Construction Materials for Existing Buildings
Small Building Size (5000-15000 s.f.)
Light (e.g. wood frame)............3100 BTU/s.f.
Medium (e.g. steel frame)..........9300
Heavy (e.g. masonry, concrete)...15,500
Medium Building Size (50,000-150,000 s.f.)
Light (e.g. wood frame)............2400 BTU/s.f.
Medium (e.g. steel frame)..........7200
Heavy (e.g. masonry, concrete)...12,000
Large Building Size (500,000-1,500,000 s.f.)
Light (e.g. wood frame)............2100 BTU/s.f.
Medium (e.g. steel frame)..........3600
Heavy (e.g. masonry, concrete)...10,500
Now, many (most) homes don't even register on the "small" scale above. But seeing as how demo energy decreases as a building size increases, we think we're being conservative by using numbers meant for 5000-15,000 s.f. buildings to calculate the demo energy of an typical single family home. In other words, the actual energy expended is probably higher.
So, back to our "model" home: 3000 s.f. frame house X 3100 BTU = 9,300,000 BTU. If the same home was made of brick, we're looking at 46,500,000 BTU. Add that to the existing embodied energy, and you're on your way to making a solid case for preserving homes from an energy conservation perspective.
* You are a NTHP Forum member, right? You should be. The journal is great and members can pick up the ACHP report on embodied energy in the pdf file cabinet. Go now!
Thursday, November 29, 2007
We looked at the embodied energy of one building. But what about a group of buildings, say, the number of wrecking permits reviewed by a North Shore HPC in 2006. Last year this HPC reviewed 85 permits. Taken together, these account for 204,920 s.f. of single family demo. That's equal to a whopping 143,444,000,000 BTUs of embodied energy. We go back to our favorite energy converter, converted our BTUs to gallons of gas, and the results are in. Envelope please...
1,148,614 gallons of gas. And at $3 a gallon the embodied energy is--or rather, in this case, was--worth $3,445,842.
Now lets get creative. Say we used our 1,148,614 gallons to fill up. We'll use the NHTSA's CAFE standards, a combined 22.2 for passenger cars and light trucks (that includes SUVs under 8,500 pounds).* 1,148,614 gallons multiplied by 22.2 miles per gallon gives us 25,499,230.8 miles. For a single vehicle, that's about 1,024 trips around the earth's equator. Whew.
Then we checked out the EPA's Personal Emissions Calculator. If we drove those 25,499,230.8 miles in a year in a vehicle with 22.2 mpg, we'd create 23,669,142 pounds of carbon dioxide. Well, we can't possibly drive 25+ million miles in a single year. The same EPA site tells us 12,100 pounds is average per vehicle per year. So divide 23,669,142 of carbon dioxide by the 12,100 pound average and... yes, it's like putting 1,956 cars on the road. That's a year's worth of demo in one town folks.
So why is embodied energy important? The greenest building does the math.
* and these are "standards," mind you, not actual on the road fuel economy numbers!